title: Interaction of PICK1 with C-terminus of growth hormone-releasing hormone receptor (GHRHR) modulates trafficking and signal transduction of human GHRHR.
abstract: Release of growth hormone (GH) from the somatotroph is regulated by binding GH-releasing hormone (GHRH) to its cognate receptor (GHRHR), one of the members of the G protein-coupled receptor (GPCR) superfamily. Proteins bound to the carboxy (C)-terminus of GPCR have been reported to regulate intracellular trafficking and function of the receptor; however, no functionally significant protein associated with GHRHR has been reported. We have identified a protein interacting with C-kinase 1 (PICK1) as a binding partner of GHRHR. In vitro binding assay revealed the PDZ-domain of PICK1 and the last four amino acid residues of GHRHR were prerequisite for the interaction. Further, in vivo association of these proteins was confirmed. Immunostaining data of a stable cell line expressing GHRHR with or without PICK1 suggested the C-terminus of GHRHR promoted cell surface expression of GHRHR and PICK1 affected the kinetics of the cell surface expression of GHRHR. Furthermore, cAMP production assay showed the C-terminus of GHRHR is involved in the regulation of receptor activation, and the interaction of GHRHR with PICK1 may influence intensities of the signal response after ligand stimulation. Thus, the interaction of the C-terminus of GHRHR with PICK1 has a profound role in regulating the trafficking and the signaling of GHRHR. [Supplementary Figure: available only at http://dx.doi.org/10.1254/jphs.12287FP].
authors.affiliation: Department of Molecular Pharmacology, Tohoku University Graduate School of Medicine, Miyagi, Japan.
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Katsushima
authors.forename: Takeya
authors.initials: T
authors.lastname: Sato
authors.forename: Chika
authors.initials: C
authors.lastname: Yamada
authors.forename: Moe
authors.initials: M
authors.lastname: Ito
authors.forename: Yuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Eishin
authors.initials: E
authors.lastname: Ogawa
authors.forename: Izumi
authors.initials: I
authors.lastname: Sukegawa
authors.forename: Jun
authors.initials: J
authors.lastname: Sukegawa
authors.forename: Kohji
authors.initials: K
authors.lastname: Fukunaga
authors.forename: Teruyuki
authors.initials: T
authors.lastname: Yanagisawa
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism / Q000502:physiology*; D003598:Cytoskeletal Proteins; D013007:Growth Hormone-Releasing Hormone / Q000378:metabolism* / Q000502:physiology*; D006801:Humans; D008297:Male; D009687:Nuclear Proteins / Q000378:metabolism / Q000502:physiology*; D054731:PDZ Domains / Q000502:physiology*; D011485:Protein Binding; D021381:Protein Transport; D017207:Rats, Sprague-Dawley; D018017:Receptors, Pituitary Hormone-Regulating Hormone / Q000378:metabolism* / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D009687:Nuclear Proteins; C498298:PICK1 protein, rat; D018017:Receptors, Pituitary Hormone-Regulating Hormone; D013007:Growth Hormone-Releasing Hormone